The present invention relates to a coaxial connector with a selector switch for cellular phones and radio sets.
Many electronic devices such as cellular phones and radio sets have on their internal printed circuit boards a coaxial connector with a selector switch for use during inspection and maintenance.
In this kind of selector switch-incorporating coaxial connector used on cellular phones, a receptacle of the connector has, for example, a construction in which a first contact connected to a transmission/reception circuit and a second contact connected to an antenna of the cellular phone are normally closed. For inspection, a coaxial plug connected with a measuring instrument is inserted into the receptacle to bring the first and second contacts out of conduction and connect the first contact to the coaxial plug.
FIG. 8 shows a conventional construction of the connector of this kind.
In the receptacle of the conventional connector shown in FIG. 8, a first contact 52 and a second contact 53 are arranged in a plug insertion hole 51 formed in a connector housing 50 made from an insulating material. The first contact 52 is connected, for example, to the above-described transmission/reception circuit of a cellular phone. The second contact 53 is connected to an antenna of the cellular phone. The plug insertion-side end of the connector housing 50 is covered with a metal shell 54 that is brought into contact with an outer conductive contact of the inserted coaxial plug.
The first contact 52 and the second contact 53 are normally in contact with each other. Accordingly, the transmission/reception circuit is connected to the antenna of the cellular phone through the first contact 52 and the second contact 53.
When, for inspection, a coaxial plug connected with a measuring instrument through a coaxial cable is inserted into the plug insertion hole 51, it pushes down the first contact 52 to part from the second contact 53. At the same time, the first contact 52 touches an exposed, center conductive contact provided at the front end of the coaxial plug. The metal shell 54 touches an external conductive (wire mesh) contact of the coaxial plug. As a result, the transmission/reception circuit is connected, through the first contact 52 and the contact of the coaxial plug, to the measuring instrument attached to the coaxial cable.
The conventional technology shown in FIG. 8 has a drawback that because the contact portion of the first contact 52 and the second contact 53 are exposed to the outside as they are, dirt and dust are trapped in the contact portion, resulting in easily generating a poor electrical contact.
FIG. 9 shows another conventional technology that overcomes the problem described above.
In this conventional technology, the contact portion of the first contact 52 and the second contact 53 are covered with an upper housing 55A. A guide hole 56, in which a selector terminal 57 is movably fitted, is formed at the upper housing 55A.
When the coaxial plug is not inserted, the first contact 52 and the second contact 53 come in contact with each other, as in the preceding example. The front flange portion 57A of the selector terminal 57 is in contact with the first contact 52 at all times.
When the coaxial plug is inserted into the plug insertion hole 51, it pushes down the selector terminal 57 and therefore the first contact 52, causing the contact portion of the first contact 52 to part from the second contact 53. As a result, the first contact 52 is connected to the center conductive contact of the inserted coaxial plug through the selector terminal 57, as with the above.
In the conventional technology shown in FIG. 9, although it is possible to prevent infiltration of dust because the contact portion of the contacts are covered, there are some problems that an impedance matching between the measuring instrument and the transmission/reception circuit is difficult, and thus, a high frequency characteristic degrades, since the selector terminal 57 comes always in contact with the first contact 52. Further, a thickness of the front flange portion 57A of the selector terminal 57 needs to have a thickness that allows for a clearance At equal to the thickness of the second contact 53 in order to ensure a reliable touch between the first contact 52 and the second contact 53. This construction may result in the front flange portion 57A of the selector terminal 57 coming into contact at one time and out of contact at other times due to the clearance at the time when vibrations are created, deteriorating the high frequency characteristic.
FIG. 10 shows still another conventional technology that overcomes these problems.
In this conventional technology, the selector terminal 57 is urged (upward) toward a coaxial plug 60 side by a coil spring 58. In the normal state in which the coaxial plug 60 is not inserted, the selector terminal 57 is out of contact with the first contact 52. An insulator 59 is interposed between the coil spring 58 and the selector terminal 57.
As shown in FIG. 10, when the coaxial plug 60 is inserted into the plug insertion hole 51, the selector terminal 57 is pushed down against the force of the coil spring 58. Accordingly, the first contact 52 is pushed down to part from the second contact 53. As a result, the first contact 52 is connected to a center conductive contact 61 of the coaxial plug 60 through the selector terminal 57, as described in the previous example. A metal shell 54 on the receptacle side touches an outer conductive contact 62 of the coaxial plug 60.
With this conventional technology, it is therefore possible to make an improvement on the problem of the deteriorated high frequency characteristic experienced with the conventional technology of FIG. 9 which is caused by the continual contact of the selector terminal 57 or by the intermittent contacting and parting action of the selector terminal 57 due to vibrations.
In the conventional technology of FIG. 10, however, the use of the coil spring 58 increases the height of the receptacle of the connector. Hence, it hinder a reduction in the size of the connector. The connector of this kind used on electronic devices such as cellular phones is normally required to have a height of the order of several millimeters and an increasingly smaller height of the receptacle of the connector is being called for.
Further, because the receptacle of the connector of this conventional technology uses a coil spring, an automatic assembly using an automated machine is difficult, making the manufacturing efficiency low. Furthermore, the use of the coil spring increases the number of parts, which is detrimental to a cost reduction.
The present invention has been accomplished under these circumstances and it is an object of the invention to provide a selector switch-incorporating coaxial connector which can realize a reduction in the connector height, make the assembly easy and reduce the parts count.
A coaxial connector with a selector switch comprising: a receptacle housing made from an insulator; a pair of contacts provided in a space formed in the receptacle housing and a point of said contacts coming in contact with each other; a onductive selector terminal movably supported in an opening formed in the receptacle housing to enable one of the pair of contacts to push in a direction that parts the paired contacts from each other; and an elastic member moving the selector terminal in a direction away from the one of the pair of contacts by an elastic recovering force thereof; wherein a pressing force of the coaxial plug as it is connected to the coaxial connector is applied to the one of the pair of contacts through the selector terminal to separate the pair of contacts from each other and to electrically connect the one of the pair of contacts to a contact of the coaxial plug through the selector terminal; wherein the elastic member is constructed from a coned disc spring or a leaf spring.
The selector terminal, for example, extends from an almost central portion of the coned disc spring or the leaf spring toward the opening in the receptacle housing.
The elastic member constructed from the leaf spring or the coned disc spring and the selector terminal can be formed in form of single-piece from a thin metal plate. The coned disc spring may be formed from a rubber material.
Because in the switch-incorporating coaxial connector of this invention the elastic member for urging the selector terminal is constructed from a coned disc spring or a leaf spring, the height of the connector structure can be reduced and the assembly during the manufacture simplified. This arrangement also allows for automated assembly using machines. If the elastic member constructed from a coned disc spring or a leaf spring and the selector terminal are formed in form of single-piece from a thin metal plate, the number of parts can be reduced contributing to a cost reduction.